• Journal of Astronomy and Space Sciences
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• v.26 no.1
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• pp.99-110
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• 2009

The main purpose of the current research is to developments a real-time Hardware In-the-Loop (HIL) simulation testbed for the satellite formation flying navigation and orbit control. The HIL simulation testbed is integrated for demonstrations and evaluations of navigation and orbit control algorithms. The HIL simulation testbed is composed of Environment computer, GPS simulator, Flight computer and Visualization computer system. GPS measurements are generated by a SPIRENT GSS6560 multi-channel RF simulator to produce pseudorange, carrier phase measurements. The measurement date are transferred to Satrec Intiative space borne GPS receiver and exchanged by the flight computer system and subsequently processed in a navigation filter to generate relative or absolute state estimates. These results are fed into control algorithm to generate orbit controls required to maintain the formation. These maneuvers are informed to environment computer system to build a close simulation loop. In this paper, the overall design of the HIL simulation testbed for the satellite formation flying navigation and control is presented. Each component of the testbed is then described. Finally, a LEO formation navigation and control simulation is demonstrated by using virtual scenario.

• Bulletin of the Korean Space Science Society
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• 2003.10a
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• pp.105-105
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• 2003

인공위성의 개발과정에서 비행모델을 만들기 전 EM (Engineering Model) 들로 구성하는 Electrical Test Bed (ETB) 를 개발하여 위성의 하니스를 포함함 각 서브시스템 전장품들의 성능을 점검하게 되고, ETB 시험기간 동안 발생된 문제점 들은 비행모델 설계와 제작에 반영하게 된다. 다목적실용위성 2호에 대한 ETB를 개발하여 각종 위성 전장품에 대한 성능과 부분품들간의 인터페이스 신호들의 점검을 성공적으로 완료하였으며, 시험기간 동안 발생된 각종 문제점들은 비행모델 설계와 제작에 이미 반영하였다. 본 논문에서는 다목적실용위성 2호 비행모델에 대한 시험을 위하여 각 서브시스템 즉, 원격측 정명령계, 전력계, 자세제어계의 전장품과 탑재소프트웨어 그리고 각종 시뮬레이터들의 구성과 전기/전자적인 기능시험을 위한 시험항목 및 방법에 대해 고찰하고자 한다.

• Proceedings of the Korean Institute of Navigation and Port Research Conference
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• 2013.06a
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• pp.105-107
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• 2013

위성항법 기반 위치정보 서비스에 대한 안정성 및 신뢰성 확보를 위해서는 위성신호의 이상 감시가 필수적이며, 특히 안전과 관련된 응용분야에서의 위성신호 이상은 안전사고와 직결될 수 있으므로 위성신호 감시는 상시 안정적으로 운용되어야 한다. 따라서 효율적인 이상감시 기법 설계와 다양하고, 지속적인 시험평가를 위해서는 테스트베드 구축이 필요하며, 테스트베드 구축을 위한 요소 중 특히, 다양한 시나리오의 신호 이상을 생성할 수 있는 이상신호 생성 기술이 필요하다. 따라서 본 논문에서는 다양한 이상신호 생성 및 실신호 특성 반영이 가능한 소프트웨어 기반 GPS 이상신호 생성기를 제안한다. 소프트웨어 기반 GPS 이상신호 생성기는 높은 확장성을 가지므로, 사용자가 적용 및 응용하기 쉬우며, 상용 신호생성 시뮬레이터와 비교하여 실신호 특성을 반영한 이상신호 생성이 가능하다.

• 한국항공운항학회:학술대회논문집
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• 2007.06a
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• pp.129-132
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• 2007

• Current Industrial and Technological Trends in Aerospace
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• v.6 no.2
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• pp.69-79
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• 2008

As the cost of the operational spacecraft simulator is a large portion of the spacecraft cost and its requirements increase, it is given the pressures to reduce the cost and the development period. For that reason, the space industry with the coordination of ESA has made a study of the reuse in a wide scope across space projects. Its scope includes not only simulation software itself but also software requirements, design, work experience and developing process/methodology. The standard for simulator model portability and the efficiency enhancement of the development process as a result have been successfully applied to several projects. This paper describes the recent trend of the spacecraft simulator in Europe and the present status of its the study and the development.

• Journal of Space Technology and Applications
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• v.2 no.2
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• pp.67-80
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• 2022

The missile early-warning satellite systems have been developed and upgraded by some space-developed nations, under the inevitable trend that the space is more strongly considered as another battle field than before. As the key function of such a satellite-based early warning system, the prediction algorithm of the missile flight trajectory is studied in the paper. In particular, the evolution computation, receiving broad attention in the artificial intelligence area, is applied to the proposed prediction method so that the global optimum-like solution is found avoiding disadvantage of the previous non-linear optimization search tools. Moreover, using the prediction simulator of the launch vehicle flight trajectory which is newly developed in C# and Python, the paper verifies the performance and the feature of the proposed algorithm.

• Journal of the Korean Society for Aeronautical & Space Sciences
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• v.36 no.5
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• pp.514-523
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• 2008

This paper presents a single-axis simulator developed to verify the attitude control algorithm of KAUSAT-2 satellite. Named KAUSatSIM, the simulator is composed of a single-axis rotation table using an air-bearing that simulates a frictionless environment, as well as sensors and momentum wheel that was used on KAUSAT-2. The simulator can be utilized for verification of KAUSAT-2 attitude control algorithm, development of new algorithms, and verification of performance. Tests were performed on the single-axis rotation simulator using the momentum wheel in order to verify the attitude control algorithm of KAUSAT-2. Satisfactory test results were obtained by designing a wheel controller that employs the proportional-derivative control method. In addition, a propulsion system was added and tested for development of a new satellite attitude control algorithm.

• Proceedings of the Korean Institute of Navigation and Port Research Conference
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• 2012.06a
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• pp.62-64
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• 2012

개선된 정확도 성능을 확보하기 위하여 보강 시스템을 이용한 많은 연구가 진행되고 있다. Network RTK는 다중 기준국의 반송파 측정치 보정정보를 이용하여 시공간 오차를 보강한 측위성능을 얻기 위한 기법으로 현재에도 꾸준히 연구되고 있다. 그러나 성능개선을 목적으로 한 알고리즘 개선안에 대한 연구는 지속적으로 연구되었지만, 무결성 확보를 위한 연구는 아직 연구된 바가 없다. 본 논문에서는 Network RTK에서의 무결성 확보를 위한 기초연구로 위성이상이 발생한 경우에 이상을 검출하고 이상 위성을 식별할 수 있는 알고리즘을 제안하였다. 그리고 시뮬레이터를 사용하여 오차 시나리오가 인가된 위성 신호를 생성하고, 이중주파수용 상용 수신기를 사용하여 수신한 데이터를 사용하여 제안한 알고리즘의 성능을 검증하였다.

• Journal of the Korea Institute of Information and Communication Engineering
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• v.14 no.10
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• pp.2223-2229
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• 2010

The integrity monitoring of anomalous GPS signal have been researched because of the degradation of GPS satellite performance. It is known that anomalous GPS signal can occur by failure of GPS satellite, sudden increase of ionosphere delay error, SA, wrong modeling for navigation parameters from control segment, and an electromagnetic wave interference, etc. In case of GPS anomaly by satellites can arise from carrier frequency, code and navigation message. In this paper, the scenarios with navigation message errors were made by using GPS simulator, and the influences of GPS navigation message error to receiver were analysed. The anomalies of preamble, bits related TOW count message, subframe ID in HOW, bits related satellite healthy, and the other navigation message errors were described and simulated. Also, the number of satellites, DOP and pseudorange are analyzed to know how the anomalous signal can affect on GPS receiver.

• Aerospace Engineering and Technology
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• v.10 no.2
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• pp.105-113
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• 2011

During the development of flight software, the processor emulator and satellite simulator are essential tools for software development and verification, which can be substituted for the actual hardware. LEO satellites being developed by KARI recently use the MCM-ERC32SC processor for on-board computer (OBC). For the flight software (FSW) development and testing, the software-based spacecraft simulator was developed using TSIM-ERC32 processor emulator from Aeroflex Gaisler. It is needed to get rid of the constraints and dependencies of TSIM-ERC32 processor emulator and to obtain high performance processor emulator to develop full satellite simulator. This paper presents the development of the ERC32 emulator based on open source dynamic translator, QEMU, as the first step. And it describes the software development and testing/debugging on the developed emulator.